The influence of vicinal SrTiO3 surfaces on the growth and ferroelectric properties of epitaxial Bi4Ti3O12 thin films

Adsorption-controlled growth conditions have been utilized to grow epitaxia l, stoichiometric, c-axis oriented Bi4Ti3O12 thin films by reactive molecul ar beam epitaxy (MBE). We have studied samples grown on vicinal (miscut) an d well-oriented (100) SrTiO3 substrates. There is a degradation in film pro perties as a function of step density (degree of miscut) on the SrTiO3 surf ace. The greater the degree of miscut of the SrTiO3, substrate, the less in tense the X-ray diffraction peak intensities of the film become, and the wi der are the rocking curve widths. The reduced film quality is further confi rmed by ferroelectric hysteresis measurements. Films grown on miscut substr ates have significant space charge contributions to the polarization, while films grown on well-oriented substrates show symmetric hysteresis loops wi th remanent polarizations approaching values obtained for bulk single cryst als. The degradation of film properties is explained by considering the inf luence of steps at the SrTiO3, substrate surface on the electronic and crys tallographic continuity in the ab plane of the deposited Bi4Ti3O12 films. ( C) 1998 Published by Elsevier Science S.A. All rights reserved.